The affected section of the pass, which links Christchurch to the West Coast, has been closed overnight for about two weeks since snow and heavy rain triggered a rockfall that overflowed onto the road at the western end of the Rock Shelter.
The work from September 9 aims to clear the material from the Rock Shelter and ensure the structure stays operational.
"To do this work requires large machinery taking up the full road width in this narrow part of the Otira Gorge," said Moira Whinham, NZTA maintenance contract manager on the West Coast.
Whinham said SH73 from Otira and Arthur’s Pass Village will be closed for four hours initially and then opened on the hour so traffic can get through.
"We understand that this work is disruptive and appreciate people’s understanding while we make this site safe and get the highway back to normal operations for the summer," said Whinham.
"We need the crane to lift the excavator onto the roof.
"The proposed time for this first closure is 10am to 2pm, Monday, 9 September.
"If the conditions are unsuitable, it will be pushed out to the next dry day.
"From Tuesday, or once the excavator is lifted onto the structure, the work will get underway clearing rock.
"This means that the road will be open daily between 7.30am and 5.30pm, with delays of up to an hour between 9am and 5pm, Tuesday to Friday that week.
"The road will be open on the hour between these times to clear traffic."
No work is planned on Saturdays or Sundays when the road will be open from 7.30am to 5.30pm.
Overnight closures continue
State Highway 73 between Otira and Arthur’s Pass will remain closed overnight between 5.30pm and 7.30am until enough work is completed to make the site safe.
Whinham said NZTA will provide an update on when the road will be fully re-opened "as soon as this is possible".
“This work is weather dependent, so it may be postponed on days where the conditions are unsuitable to work.
"In these cases, the road will be open during the day if it is safe to do so.
"There are many variables to ensure this work can occur safely each day, which means that work plans may change at short notice.
"We appreciate people’s patience while we progress this work as quickly as possible.”
Lewis Pass alternative route
To avoid delays take the Lewis Pass route via Waipara and Reefton/SH7, which will add about 60min to the journey between Christchurch and the West Coast.
- Any changes to route availability will be updated on the Journey Planner at all times.
- Electronic signs at each end of SH73 in places like Kumara Junction and Springfield will let people know the open hours that day.
- This work is expected to take up to six weeks to complete, subject to weather.
- As the crew moves more material, NZTA will have more confidence on the likely duration.
- An update will be provided each Friday to confirm the closures for the following week.
- There may be other maintenance work on SH73 which may increase travel times. Check the journey planner to ensure you have enough time to reach the road block points either side.
